Heated commercial vehicle urea pressure sensor

Abstract

The utility model provides a kind of heating type commercial vehicle urea pressure sensor, including shell, outer cover, detection core, internal support and circuit board, the detection diaphragm of detection core bottom is sealed communication with urea delivery pipe bottom of shell, and urea delivery pipe is provided with electric heating coil along its length direction;Circuit board is set in the detection core top by internal support, and with detection core and circuit board electric connection.The utility model passes through integrated electric heating coil and outside internal temperature control switch, environmental temperature control switch, effectively solve the crystallization problem of commercial vehicle urea pressure sensor under low temperature environment;And its structure design is compact and reliable, easy to produce and maintain, applicable to various commercial vehicle type, with higher market application value.

Description

Technical Field

[0001] This utility model relates to the field of pressure sensor technology, and in particular to a heated pressure sensor for urea systems in commercial vehicles, which can prevent urea solution from crystallizing in low-temperature environments, ensuring reliable sensor operation and system safety. Background Technology

[0002] With increasingly stringent environmental regulations, commercial vehicle diesel engines must meet China VI emission standards and commonly employ Selective Catalytic Reduction (SCR) systems to reduce nitrogen oxide (NOx) emissions. Urea solution, as a key reducing agent in the SCR system, is injected into the high-temperature exhaust pipe and decomposes into ammonia, which reacts with NOx to produce nitrogen and water vapor. However, urea solution has a tendency to crystallize: when the ambient temperature is below -11°C, the urea solution crystallizes, expanding in volume by approximately 7%, leading to blockages or ruptures in urea delivery pipelines, sensors, and other components.

[0003] In existing technologies, the primary function of urea pressure sensors in commercial vehicles is to monitor the pressure of the urea system and transmit the signal to the vehicle control unit (DCU). However, traditional sensors lack a heating mechanism. In cold regions, after the vehicle is turned off, the crystallization and expansion of the urea solution often damages the internal structure of the sensor (such as diaphragm rupture or shell cracking), leading to system failure and increased maintenance costs. Although some automakers have optimized the heating of urea pipelines or tanks, there is still a technological gap in the heating protection of the pressure sensor itself, which cannot fundamentally solve the sensor failure problem caused by crystallization.

[0004] Therefore, there is an urgent need for a urea pressure sensor with integrated heating function that can automatically heat up in low-temperature environments to prevent urea solution from crystallizing, while avoiding the risk of overheating and improving the reliability and adaptability of the system. Utility Model Content

[0005] This invention addresses the problem of urea pressure sensors being damaged by urea solution crystallization in low-temperature environments by existing technologies. It provides a heated commercial vehicle urea pressure sensor that integrates an electric heating coil and a temperature control system to achieve automatic heating at low temperatures and overheat protection, ensuring stable operation of the sensor in harsh environments.

[0006] To solve the above-mentioned technical problems, this utility model adopts the following technical solution:

[0007] A heated urea pressure sensor for commercial vehicles includes: a housing, an outer cover disposed on the top of the housing, a detection core disposed within the inner cavity of the housing, an internal support, and a circuit board, wherein:

[0008] The detection diaphragm at the bottom of the detection core is sealed and connected to the urea delivery pipe at the bottom of the outer shell, and an electric heating coil is provided on the urea delivery pipe along its length; the circuit board is set on the top of the detection core through an internal bracket and is electrically connected to the detection core and the circuit board to realize pressure signal processing and heating control.

[0009] Preferably, the outer casing includes a housing, the urea delivery pipe, and the electric heating coil, wherein:

[0010] The bottom of the housing is provided with an integrally formed urea delivery pipe, and the electric heating coil is embedded in the outer periphery of the urea delivery pipe in a spiral shape to ensure uniform heating and compact structure.

[0011] Preferably, the housing is a square groove structure with an open top, and a boss mounting seat for mounting the detection core is provided at the bottom of the groove. A sealing ring is fitted on the boss mounting seat to ensure sealing.

[0012] Preferably, the boss mounting base has a detection hole at its axial center that communicates downward with the urea delivery pipe, and a limiting slot for installing the internal support is provided at the bottom of the groove on its left side.

[0013] Preferably, the urea delivery pipe has a straight pipe structure, with a first quick-release connector at the inlet at one end and a second quick-release connector at the outlet at the other end, which facilitates quick installation and replacement.

[0014] More preferably, the housing further includes an external connector electrically connected to the circuit board, wherein:

[0015] The external plug is located on the left side wall of the housing and is integrally formed with the housing, which simplifies wiring and improves reliability.

[0016] Preferably, the bottom of the detection core is provided with a ceramic diaphragm with an integrated thick film resistor, and the top is provided with a connector terminal for electrically connecting to the circuit board. The ceramic diaphragm is arranged facing downwards and directly opposite the detection hole at the bottom of the housing to achieve high-precision pressure detection.

[0017] Preferably, the internal support includes a support plate, a support rod, a first baffle, and a second baffle, wherein:

[0018] The support plate has a U-shaped structure, and the opening at its right end is set as a clearance hole for installing the connector terminal at the top of the detection core;

[0019] The top of the support rod is vertically disposed at the bottom right end of the support plate, and its lower end is embedded in the limiting slot inside the outer shell cavity.

[0020] The first baffle and the second baffle are two sets, which are respectively arranged vertically at the top of the left and right ends of the support plate at a front-to-back interval, and are used to limit the installation of the circuit board.

[0021] Preferably, the left end of the support plate is provided with a limiting post and a threaded hole for limiting the installation of the circuit board, wherein:

[0022] The limiting post and the threaded hole are arranged in a staggered manner; and the limiting post and the threaded hole are two sets, arranged symmetrically front and back.

[0023] Preferably, the left end of the circuit board has two sets of first limiting holes and second limiting holes, which are arranged corresponding to the limiting post and the threaded hole, wherein:

[0024] The first limiting hole is fitted onto the limiting post, and the second limiting hole is connected to the threaded hole by a screw.

[0025] Preferably, the electric heating coil is connected to the internal temperature control switch, the ambient temperature control switch and the vehicle power supply via the circuit board through wires, so as to realize automatic start-up at low temperatures and overheat protection.

[0026] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0027] (1) High efficiency in preventing crystallization: The urea delivery pipe is directly heated by an electric heating coil, which can quickly prevent the urea solution from crystallizing in a low-temperature environment, avoid sensor damage caused by volume expansion, and extend sensor life.

[0028] (2) Intelligent temperature control: It adopts dual control of ambient temperature control switch and internal temperature control switch. When the ambient temperature is below -10℃, it automatically starts heating and when the internal temperature is above 15℃, it automatically shuts off to prevent overheating failure and improve safety and energy efficiency.

[0029] (3) Uninterrupted operation: The heating power supply is directly connected to the vehicle power supply, and can continue to work after the vehicle is turned off, ensuring that the sensor can start normally after a long period of parking in cold regions.

[0030] (4) Compact and reliable structure: The urea pressure sensor adopts an integrated design, reducing external pipelines. The sealing structure and internal bracket enhance the sensor's shock resistance and stability, making it suitable for harsh working conditions in commercial vehicles.

[0031] (5) Easy to maintain: The urea pressure sensor can be quickly connected and disconnected from the urea delivery pipeline and vehicle power supply through quick-release connectors at both ends of the urea delivery pipe and an integrated external plug, which facilitates installation and replacement and reduces maintenance costs. Attached Figure Description

[0032] Figure 1This is a three-dimensional structural diagram of a heated urea pressure sensor for commercial vehicles according to this utility model. Figure 1 ;

[0033] Figure 2 This is a three-dimensional structural diagram of a heated urea pressure sensor for commercial vehicles according to this utility model. Figure 2 ;

[0034] Figure 3 This is a schematic diagram of the main structure of a heated commercial vehicle urea pressure sensor according to the present invention;

[0035] Figure 4 This is a cross-sectional view of a heated commercial vehicle urea pressure sensor according to the present invention.

[0036] Figure 5 This is an exploded view of the structure of a heated urea pressure sensor for commercial vehicles according to this utility model. Figure 1 ;

[0037] Figure 6 This is an exploded view of the structure of a heated urea pressure sensor for commercial vehicles according to this utility model. Figure 2 ;

[0038] Figure 7 This is a schematic diagram of the detection core in a heated commercial vehicle urea pressure sensor according to this utility model. Figure 1 ;

[0039] Figure 8 This is a schematic diagram of the detection core in a heated commercial vehicle urea pressure sensor according to this utility model. Figure 2 ;

[0040] Figure 9 This is a schematic diagram of the internal support structure of a heated commercial vehicle urea pressure sensor according to this utility model. Figure 1 ;

[0041] Figure 10 This is a schematic diagram of the internal support structure of a heated commercial vehicle urea pressure sensor according to this utility model. Figure 2 ;

[0042] Figure 11 This is a schematic diagram of the connection structure between a heated commercial vehicle urea pressure sensor, an ambient temperature control switch, and an internal temperature control switch according to this utility model.

[0043] The accompanying figures are labeled as follows:

[0044] 100-Outer shell, 110-Housing shell, 111-Boss mounting base, 112-Detection hole, 113-Sealing ring, 114-Limiting slot, 115-Sealing groove; 120-Urea delivery pipe, 121-First quick-release connector, 122-Second quick-release connector; 130-Electric heating coil, 140-External plug;

[0045] 200 - Outer cover, 201 - Sealing gasket;

[0046] 300 - Detection core, 301 - Ceramic diaphragm, 302 - Connector terminal;

[0047] 400-Internal bracket, 401-Support plate, 402-Allowing hole, 403-Support rod, 404-First baffle, 405-Second baffle, 406-Limiting post, 407-Threaded hole;

[0048] 500 - Circuit board, 501 - First limiting hole, 502 - Second limiting hole;

[0049] 600-Vehicle power supply;

[0050] 700-Ambient temperature control switch;

[0051] 800 - Internal temperature control switch. Detailed Implementation

[0052] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0053] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0054] In some embodiments, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, a heated commercial vehicle urea pressure sensor is provided, mainly including a housing 100, an outer cover 200, a detection core 300, an internal bracket 400, and a circuit board 500. Its core solution is to achieve automatic heating at low temperatures and overheat protection by integrating an electric heating coil 130 and a temperature control system, ensuring stable operation of the sensor in harsh environments, and effectively solving the problem of damage to urea pressure sensors in the prior art due to urea solution crystallization in low-temperature environments.

[0055] Specifically, the outer casing 100 consists of a housing 110, a urea delivery pipe 120, and an electric heating coil 130. The housing 110 is a square groove with an open top, and a straight tubular urea delivery pipe 120 is integrally formed at the bottom. The electric heating coil 130 is spirally embedded in the outer periphery of the urea delivery pipe 120 to achieve uniform heating.

[0056] The detection core 300 is fixed to the inner cavity of the housing 110 via the boss mounting base 111. The bottom ceramic diaphragm 301 faces the detection hole 112 and is sealed and connected to the urea delivery pipe 120. The circuit board 500 is fixed to the top of the detection core 300 via the internal bracket 400 and is electrically connected to the detection core 300 via the connector terminal 302. The external plug 140 is located on the left side wall of the housing 110 and connects to the circuit board 500 for external signal transmission.

[0057] After the sensor is powered on, the circuit board 500 receives the feedback signal from the detection core 300. When the urea pump builds up pressure, the urea solution pressure acts on the ceramic diaphragm 301, causing a change in the output of the Wheatstone bridge with integrated thick-film resistors. The signal conditioning chip (such as JHM1102) on the circuit board 500 converts the pressure signal into a 0.5-4.5V voltage signal and outputs it to the vehicle's DCU. 0.5V corresponds to atmospheric pressure, and 4.5V corresponds to full-scale pressure, enabling real-time pressure monitoring. If the output voltage is abnormal (such as below 0.5V or above 4.5V), the DCU can determine that the sensor is faulty or the system pressure is abnormal.

[0058] An ambient temperature control switch 700 monitors the ambient temperature in real time and automatically closes when the temperature drops below -10°C. The electric heating coil 130 draws power from the vehicle power supply 600 via circuit board 500 to heat the urea delivery pipe 120, preventing urea crystallization. An internal temperature control switch 800 monitors the temperature of the urea solution at the catalyst inlet and automatically disconnects when the temperature exceeds 15°C, stopping heating and preventing overheating. This dual temperature control mechanism ensures a safe and efficient heating process.

[0059] In some of the embodiments, such as Figures 1 to 6 As shown, the housing 110 of the outer shell 100 is integrally injection molded from engineering plastic, the urea delivery pipe 120 is a corrosion-resistant metal pipe, and the electric heating coil 130 is a nickel-chromium alloy wire, which is embedded in the pipe wall of the urea delivery pipe 120 to improve the heat conduction efficiency.

[0060] The first quick-release connector 121 and the second quick-release connector 122 at both ends of the urea delivery pipe 120 adopt a standard snap-fit ​​design for easy and quick connection with the urea pipeline. The external plug 140 is integrated on the left side of the housing 110 and is connected to the circuit board 500 via a crimp terminal, reducing soldering points and improving reliability.

[0061] Urea solution flows into the urea delivery pipe 120 through the inlet, and after being heated, flows out through the outlet. The electric heating coil 130 generates Joule heat through current, directly heating the pipe wall and maintaining the urea solution temperature above its crystallization point. A quick-release connector allows for rapid disassembly, facilitating cleaning or sensor replacement.

[0062] Specifically, the housing 110 is a square groove structure with an open top. The bottom of the groove is provided with a boss mounting seat 111 for installing the detection core 300. A sealing ring 113 is fitted on the boss mounting seat 111. After all components are installed and sealant is injected, the outer cover 200 is covered and pressed tightly so that the sealing gasket at the bottom of the outer cover 200 is aligned with the sealing groove at the top opening of the housing 110. The cover is then locked with bolts, thereby sealing the bottom of the detection core 300 on the boss mounting seat 111 through the sealing ring 113.

[0063] The boss mounting base 111 has a detection hole 112 at its axial position, which communicates downward with the urea delivery pipe 120. This allows the detection hole 112 to communicate with the ceramic diaphragm 301 at the bottom of the detection core 300, enabling real-time monitoring of the urea pressure within the detection hole 112. Simultaneously, a limiting slot 114 for installing the internal support 400 is provided at the bottom of the groove on the left side of the housing 110.

[0064] In some of these embodiments, such as Figures 5 to 10 As shown, the ceramic diaphragm 301 of the detection core 300 integrates a Wheatstone bridge through a thick-film printing process, providing high precision and corrosion resistance. The connector terminal 302 uses gold-plated leads to ensure a stable electrical connection with the circuit board 500.

[0065] The support plate 401 of the internal bracket 400 has a U-shaped structure, with a right-end clearance hole 402 to accommodate the connector terminal 302, and the lower end of the support rod 403 is inserted into the limiting slot 114 for fixation. The first baffle 404 and the second baffle 405 clamp the circuit board 500 from the front and rear directions. The limiting post 406 and the threaded hole 407, through the first limiting hole 501 and the second limiting hole 502, cooperate with the screw 503 to fix the circuit board 500 and prevent it from loosening due to vibration.

[0066] The internal support 400 not only provides mechanical support but also ensures precise alignment between the circuit board 500 and the detection core 300 through baffles and limiting structures. During the detection process, the deformation of the ceramic diaphragm 301 outputs a micro-voltage signal through a bridge circuit, which is amplified and conditioned by the circuit board 500 to output a standard voltage signal.

[0067] In addition, such as Figure 11As shown, the electric heating coil 130 is connected to the internal temperature control switch 800, the ambient temperature control switch 700, and the vehicle power supply 600 via the circuit board 500. The ambient temperature control switch 700 is installed outside the sensor to sense the ambient temperature; the internal temperature control switch 800 can be installed on the urea delivery pipeline before the urea tank or catalyst inlet as needed to monitor the temperature of the urea solution in real time. The circuit board 500 integrates control logic; when the ambient temperature control switch 700 is triggered, the relay closes, and heating starts; the internal temperature control switch 800 serves as redundant protection to prevent overheating.

[0068] Combination Figures 1 to 11 As shown, the working principle of this heated commercial vehicle urea pressure sensor is as follows: After the vehicle is turned off, the vehicle power supply 600 continues to supply power, and the heating system remains operational. For example, when parking at night in cold regions, the ambient temperature control switch 700 continuously monitors the temperature. Once the temperature falls below a threshold, heating is activated to prevent urea crystallization. The internal temperature control switch 800 ensures that the heating temperature does not exceed a safe range, protecting the internal components of the sensor.

[0069] The heated urea pressure sensor for commercial vehicles provided by this utility model effectively solves the crystallization problem of urea pressure sensors in low-temperature environments by integrating an electric heating coil 130 and external internal temperature control switch 800 and environmental temperature control switch 700. Furthermore, the sensor has a compact and reliable structure, is easy to manufacture and maintain, is suitable for various commercial vehicle models, and has high market application value.

[0070] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0071] Secondly, the accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other.

[0072] Finally, the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A heated urea pressure sensor for commercial vehicles, characterized in that, include: The housing (100), the outer cover (200) disposed on the top of the housing (100), the detection core (300), the internal support (400) and the circuit board (500) disposed in the inner cavity of the housing (100), wherein: The detection membrane at the bottom of the detection core (300) is sealed and connected to the urea delivery pipe (120) at the bottom of the outer shell (100), and an electric heating coil (130) is provided on the urea delivery pipe (120) along its length direction; the circuit board (500) is provided on the top of the detection core (300) through an internal bracket (400), and is electrically connected to the detection core (300) and the circuit board (500).

2. The heated commercial vehicle urea pressure sensor according to claim 1, characterized in that, The outer casing (100) includes a housing (110), the urea delivery pipe (120), and the electric heating coil (130), wherein: The bottom of the housing (110) is provided with an integrally formed urea delivery pipe (120), and the electric heating coil (130) is embedded in the outer periphery of the urea delivery pipe (120) in a spiral shape.

3. The heated commercial vehicle urea pressure sensor according to claim 2, characterized in that, The housing (110) is a square groove structure with an open top. The bottom of the groove is provided with a boss mounting seat (111) for installing the detection core (300), and a sealing ring (113) is fitted on the boss mounting seat (111).

4. The heated commercial vehicle urea pressure sensor according to claim 3, characterized in that, The boss mounting base (111) has a detection hole (112) at its axial position that is connected to the urea delivery pipe (120) downward, and a limiting slot (114) for installing the internal bracket (400) is provided at the bottom of the groove on its left side.

5. The heated commercial vehicle urea pressure sensor according to claim 2, characterized in that, The housing (100) further includes an external connector (140) electrically connected to the circuit board (500), wherein: The external plug (140) is disposed on the left side wall of the housing (110) and is integrally formed with the housing (110).

6. The heated commercial vehicle urea pressure sensor according to claim 1, characterized in that, The bottom of the detection core (300) is provided with a ceramic diaphragm (301) with an integrated thick film resistor, and the top is provided with a connector terminal (302) for electrically connecting the circuit board (500). The ceramic diaphragm (301) is arranged facing downwards and directly opposite the detection hole (112) at the bottom of the outer shell (100).

7. The heated commercial vehicle urea pressure sensor according to claim 1, characterized in that, The internal support (400) includes a support plate (401), a support rod (403), a first baffle (404), and a second baffle (405), wherein: The support plate (401) has a U-shaped structure, and the opening at its right end is configured as a clearance hole (402) for installing the top connector terminal (302) of the detection core (300). The top of the support rod (403) is vertically disposed at the bottom right end of the support plate (401), and its lower end is embedded in the limiting slot (114) of the inner cavity of the outer shell (100). The first baffle (404) and the second baffle (405) are two sets, which are respectively arranged vertically at the top of the left and right ends of the support plate (401) at a front-to-back interval, and are used to limit the installation of the circuit board (500).

8. The heated commercial vehicle urea pressure sensor according to claim 7, characterized in that, The left end of the support plate (401) is provided with a limiting post (406) and a threaded hole (407) for limiting the installation of the circuit board (500), wherein: The limiting post (406) and the threaded hole (407) are arranged in a staggered manner; and the limiting post (406) and the threaded hole (407) are two sets, arranged symmetrically front and back.

9. The heated commercial vehicle urea pressure sensor according to claim 8, characterized in that, The left end of the circuit board (500) has two sets of first limiting holes (501) and second limiting holes (502) corresponding to the limiting post (406) and the threaded hole (407), wherein: The first limiting hole (501) is fitted onto the limiting post (406), and the second limiting hole (502) is connected to the threaded hole (407) by a screw (503).

10. The heated commercial vehicle urea pressure sensor according to claim 1, characterized in that, The electric heating coil (130) is connected to the internal temperature control switch (800), the ambient temperature control switch (700) and the vehicle power supply (600) via the circuit board (500) through wires.

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